Plug connector



. p 7, 194a. c. F. HART 2,448,592

PLUG CONNECTOR Filed June 10, 1943 INVENTOR.

50 azy/W;

Patented Sept. 7, 1948 UNITED STATES PATENT OFFICE Y t l 2,448,592 '7 i1 l p PLII'G CONNECTOR Carl F. Hart, Miami, Fla., assignor oir'one-third to Carl J. Frederickson andone-third to Paul J. Mueller,Miami, Fla. l 7. Application June 10, 1943,:Serial n 490,317

This invention relates to a plug connector of the type described in myco-pendingapplication of the same title filed March 14, 1941,.Serial No.383,428, now abandoned and has for an object to improve the aboveidentified structure by providing stop flanges on the central terminal,and on the conductor of the outer terminal, of the plug member adaptedto engage the contact shoes of the contact prongs of the cap member andlimit rotation of the cap member in the bayonet joint connection betweenthe cap member and the plug member so'thatthe operator may be assuredthat good electrical connection has been made when axially turningmovement of the cap member ceases during application of the cap memberto the plug member.

A furtherobject is to simplify the construction of the above identifiedstructure by. decreasing the number of parts constituting theplug'memher and the cap member. 1

A further object is to improve the anchoring of the contact prongs tothe cap member,

A further object is to improve the construction of the guide bar of thebayonet joint connection by increasing the width of a portion of theopening in the plug member ,whichreceives the guide bar of the capmember, andforming the guide bar with a similar portion of increasedWidth to the end that the plug member and. cap member will be polarizedthat is the live contact prong will always engage the live side of theelectric circuit while the other prong will engage the ground side ofthe electric circuit.--

A further ob ect is to provide apparatus of this character which willbe, formed of a few strong, a

s mple and durable parts, which will be inexpensive to manufacture, andwhich will not easily get out of order.

With the above and other obiects in view the invention consists ofcertain noveldetails "of construction and combinations of parts hereinafter fully described and claimed, it being understood that variousmodifications may be resorted to within the scope, of the appended claimwithout departing from the spirit or sacrificing any of the advantagesof the invention. v V In the accompanying. drawing forming a part ofthis specification: r Figure 1 is a longitudinal sectional viewof' a 1Claim. (01. ire-343i f plugconnector constructed in accordancewiththe-invention. 1 i t P i T Figure 2 is a cross sectional View ofthelplug connector takenon the line 2-2 of Figure 1. i

I Figure- 3 is a top plan view of the cap member shown in'Figure l, witha portion shown in section taken onthe line 33 of Figure-1.

- Figure ll-is a cross sectional view of the cap membertaken-on the line44 of Figure 3.

Figure 5 isa bottom plan view of'the plug member shown inFigure'l. y a

igure'fi is adeta'il perspectiveview of one of the conductors forterminals of the plug member showing the stop fiange thereof. r l 1Figure '7 is a detailperspective view of one of the contact prongs ofthe cap member showing theoutwardly bent lower end having anopening to,receive: thematerial of the cap, member to form-an anchorp. g I

Figure 8 is a top 'plan view of'amodified form of cap member with aportion of vthe icontact prongsand a portionv of theguide bar-shown insection: y 1 I Figure 9 is a'detail perspective view of one of themodifiediforms of contact prongs shown in-Figure 8. i J -Figure'10; is abottom, plan view of amodified formof plugmember, drawn to reducedscale; Referring now to thedrawingiorming apart of this specification,the cap member of the plug connector comprises a body IE! formed ofinsulatingmater-ial having a reducedtubularend H adapted to receiveanelectric. cord I2 of the usual type, carrying two circuit wires l3. Ashort substantially cylindrical guide bar l'lp ro je cts from ,the axisof the body opposite the reducedend and the top faceof the body '15provided with a countersink I8 at the base of the guide bar. The guidebar is provided with diametrically oppositely disposed fiat faces 19,see Figure 2. 'A pair of contact prongs 20, one of which is shown inFigure '7, extends longitudinally on the'fiat faces of the guide barflEach contact prong is formed with an outwardly bent anchoring end 2!adapted to be-embe'dded in the material of the cap member and providedwith an opening 22' to receive the material of the cap member forlocking the contactprong in place. Each contact prong is provided withathreaded opening 23 to receive a respective screw '24, see Figure 1, forattaching one of the circuit wires i3 to the prong. Each prong at theupper end is provided with a contact shoe 24' formed preferably bybending the upper end of the prong outwardly, downwardly and theninwardly, see Figure 7.

The plug member comprises a body 25 formed of insulating material havinga cylindrical opening 26 extending from the upper end to nearly thelower end of the body, there being a guide opening 21 formed axially inthe lower end of the body communicating with the opening 25 and ofsufficient diameter to permit the guide bar I! being passed therethrough into the opening 26. The bottom face of the body is concave asshown at 28 so that the guide bar may be easily guided into the opening21.

The opening 21 is provided with diametrically oppositely disposedrecesses 29 and 30, see Figure 5, which coact with the opening informing a bayonet slot. When the guide bar H is brought. intoregistration with the opening 21, the cap member may be rotated untilthe shoes 24 of the contact prongs 20 register with the recesses 29 and30 whereupon the cap. member, by rectilinear movement, may be thrustagainst the plug memher to permit the guide bar and shoes of the contactprongs entering the opening 26 of the plug member. The-reupon the capmember is turned axially to dispose. the. shoes 24' of thecontact prongsout of register with the recesses 29; and 30 so that the contact prongscannot be accidentally retracted butv must be again given a quarter turnin a retrograde direction to be brought into register with the recesses29 and 30 before the cap member and the. plug member can bedisassembled. l

Preferably the recess 30 is of greater width than the recess 29- and oneof the contact. shoes 24% is of greater width than the other contactshoe. This construction polarizes the bayonet slot since the wider shoemust be brought into register with the wider openingw'before the plugconnector can be asembled. The purpose or this is to connect the livecontact prong of the plug connector with the live side of the electriccircuit while the other prong will engage the ground side ofthe-electric circuit.

A pair of conductors 3|, one of which is shown in Figure 6, is disposeddiametrically opposite each other in the opening 26. The lower end ofeach conductor is provided with an arcuate contact head 32 adapted toengage the shoe 24 of a respective contact prong 20. The contact head isprovided with a stopflange 33 which extends radially in the opening 26when the contact head 32 extends along the cylindrical wall of theopening, see Figure 2, The stop flanges 33 are disposed out of alignmentwith each other on opposite sides of the axis of the plug member.Consequently when the guide bar I! and the shoes of the contact prongsare passed into thelopening 26 of the plug member through the bayonetjoint and given a part revolution the. contact shoes will engagerespective stop flanges 33 and halt rotation of the cap member. Theoperator is then assured that the shoes are in good electrical contactwith the arcuate heads 32' and with the stop flanges 33 of theconductors.

One of the conductors 3| is provided with a hook at the upper endadapted to engage over the upper end of the plug member. An outercylindrical contact 35 of the usual screw threaded type 4 is sleeved onthe plug member and has an electrical contact with the hook 34.

The other conductor 3| is provided with a resilient inclined free end 36which extends radially along the upper end of the body to form thecentral terminal or contact of the plug connector.

Both conductors 3| are wedged firmly in place in the opening 26 of theplug member through the medium of a wedge member 31 having an opening 38to permit the central contact 36 to be exposed exteriorly of the wedgemember. The wedge member is provided with a flange 38' which clamps theouter cylindrical contact 45 firmly against the upper end of the plugmember 25.

As shown in Figure 4 the cap member ID is provided with passages 39through which the circuit wires 13 enter the countersink 18 forapplication to the screws 24.

A modified form of cap member is shown in Figure 8 in which the onlydifierence over the cap member heretofore described is that theconductor prongs 40 are not imbedded in the material of the cap memberbut rather are equipped with base flanges H which extend along thebottom of the countersink l8 and are secured to the cap member by screws42 passed through openings 43 in, the base flange 4|. An additionalscrew M is, passed through an opening 45 in the base flange to receive acircuit wire which projects from the respective passage 39.

It: is not essential that the recesses 29 and 3B of the opening, 21- invthe plug member be of re spcctivelydifierent widths. As shown in Figure10 both recesses 46 may be formed of identical width.

Since the operation of the parts has been described as the descriptionof the parts progressed it is thought the invention will be fullyunderstood without further explanation.

What is claimed is:

In an electric plug connector, a plug body having a centrally disposedcylindrical opening extending inward from the inner end thereof with theopposite end provided with an annular flange having a concave undersurface and with a centrally disposed opening in axial alignment withand communicating with said cylindrical opening, said opposite endhaving diametrically opposedrecesses at the sides of said centrallydisposed opening, a pair of diametrically opposed conductors extendinglengthwise in said cylindrical opening and positioned against the Wallof said plug body, arcuate contact head portions extendingcircumferentially from said conductors and each terminating in a planecorresponding with the inner ends of the recesses, stop flangesextending radially from said head portions, a plug wedged in saidcylindrical opening securing said conductors against the walls of theplug body, one of said conductors extending through said wedge plug andterminating in a free end portion forming one external contact, theother of said conductors extending out of the opening and over the edgeof the plug body, a threaded sleeve positioned over the said plug bodyanchoring the end of the conductor extending over the edge of the. plugbody providing another external contact, a plug cap having a guide barwith oppositely disposed. flat sides projecting at the inner end adaptedto be inserted in the centrally disposed opening in the saidopposite endof the plug body, said cap having a counterbore around the base of theguide bar, contact prongs with shoes at the outer ends thereofpositioned against the flat sides of the guide bar, said contact prongs5 and shoes adapted to enter the recesses in the said opposite end ofthe plug body with the guide bar in the centrally disposed opening, saidcap having a neck of reduced diameter on the end opposite to the endcarrying the guide bar, and means connecting wires of an electric cordentering the cap through the neck to the contact prongs in the saidcounterbo-re.

CARL F. HART.

REFERENCES CITED The following references are of record in the file ofthis patent:

Number Kostal Mar. 3, 1942

